Biasing the pacemaker in the behavioral theory of timing.

The team used a two-key setup with pigeons. One key paid off on a timed schedule. The other key paid off on a variable schedule.

They shifted the payoff ratio between the two keys. Then they watched how the birds’ internal clock sped up or slowed down.

When the timed key gave more food, the bird’s clock ticked faster. When the other key gave more food, the clock ticked slower.

The clock did not follow total food. It followed the relative rate of food for the timed side.

Pierce et al. (1983) first said animals match relative, not absolute, payoff. The new study shows this rule reaches all the way down to the internal timer.

Davison et al. (1989) found that overall reinforcer rate did not sway time allocation. That null result looked like a clash, but the two studies tested different things. M et al. changed total food while keeping the ratio even; A et al. kept total food steady while tilting the ratio. Once you see the methods, the papers agree: only the ratio matters.

Katz et al. (2003) later showed birds can track a ratio that flips every few seconds. Their fast-tracking data extend the pacemaker idea into a live-updating world.

Your client’s “clock” for chores, breaks, or screen time may speed up or slow down based on which option pays off more right now. If you want a child to wait longer, tilt the payoff toward waiting. If you want quicker shifts, tilt it toward the next task. Watch the ratio, not the total tokens.